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worty [1.4K]
3 years ago
9

How do scientists know when a chemical change or chemical reaction has taken place.?

Chemistry
2 answers:
amm18123 years ago
5 0
 One of the clues are that there will be a change in temperature. Usually when a reaction takes place heat will be absorbed or released resulting in a change of temperature. Hope this helped!
Novay_Z [31]3 years ago
5 0
A chemical change is slightly the same as a chemical reaction. Except, the mass in a chemical reaction would be conserved, while in a chemical change, that may not happen. 
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Alekssandra [29.7K]

Answer:

2.222 that is the answer i think might want to ask

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3 years ago
I need help pleaseee help please! <3
kobusy [5.1K]

(a) The temperature goes up by 3⁰C.

(b) There is increase in temperature, so the reaction is exothermic.

(c) Examples of exothermic reaction include, rusting of Iron, burning of coal, reaction of strong acid and water.

(d) Examples of endothermic reaction include, melting solid salts and evaporating liquid water.

<h3>What is exothermic reaction?</h3>

Exothermic reaction is a type of chemical reaction in which energy is transferred to or from the surroundings.

Examples of exothermic reactions include the following;

  • Rusting of Iron
  • Burning of Coal
  • Reaction of Strong Acid and Water
  • Water and Calcium Chloride

<h3>What is endothermic reaction?</h3>

Endothermic reaction is a type of chemical reaction in which energy is absorbed from the surroundings.

Examples of endothermic reactions include the following;

  • Melting solid salts.
  • Evaporating liquid water, etc

<h3>Change in temperature</h3>

From the increase in temperature from 15⁰C to 23⁰C, we can conclude that the temperature goes up by 3⁰C.

20⁰C - 17⁰C = 23⁰ - 20⁰C = 3⁰C.

Since there is increase in temperature, the reaction is exothermic.

Learn more about exothermic reaction here: brainly.com/question/2924714

#SPJ1

4 0
1 year ago
Aside from direct harm, what secondary issue do invasive species present?
solniwko [45]

Answer:

B

Explanation:

6 0
3 years ago
A balanced equation for the dissociation of KI
Ann [662]

Answer:

The balanced equation for the dissociation of KI is

KI →  K⁺ + I⁻

Explanation:

KI is the potassium iodide.

K⁺ comes from the KOH, a strong base, so the cation is the conjugate weak acid and in water it does not react.

I⁻ comes from HI, a strong acid, so the anion is the conjugate weak base and in water it does not react.

K⁻  + H₂O ← KOH + H⁺

I⁻ + H₂O ← HI + OH⁻

That's why the arrow in the reaction is in the opposite direction.

3 0
3 years ago
Help answer the questions in the photo above
DanielleElmas [232]

Let the person at the Left be A and Person at the right be B

then the force by person A will be

Pulling force + Frictional Force = the force by the person

which is,

20N+11N=29N

then the force by person B will be,

25N+5N=30N

1) the net force will be 30N-29N=1N

2) the force are unbalanced as the net force acting on the object is not zero.

3) the rope will move towards the right as there is a net force of 1N towards the right.

5 0
3 years ago
Read 2 more answers
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